We currently use Stripe and even though we charge sales tax in our own country, we are approaching "economic nexus" in some US states and thus are looking at options like TaxJar and Avalara to sit on top of Stripe, or even full switches to something like Paddle or FastSpring. We love Stripe and switching would be painful, but there is concern that a patched together solution could create more problems than it's worth for our small team. Ideally we want something that will handle tax calculation at checkout, do filing (and even better registration) for us, and also keep track of approaching Nexus in other jurisdictions.
Hey there! I'm a PM at Stripe working on all things sales tax. We've been working on some new features to better address these pain points for our users and I'd be happy to share a bit more what we're working on via email (kmoriarty@stripe.com) and see if our timelines you work out for what you're aiming to do. Overall, would be great to hear if you have any other items on your tax wishlist as well.